anyone ever tried it? i was thinking some sort of small, airtight enclosure like those spheres (sorry, i forgot who did them), but add nothing inside, and make it a complete vacuum.
the sound will be obvioulsy softer, because u are effectively killing all the sound and air that is moved from the back of the speaker, but you are also killing all the distortion and unwanted resonances that come with it. The spider and cone would also meet with less resistance when trying to move.
I dont need things to be very loud, so should i give this a shot? i can imagine that it might be dangerous for the driver if done without caution, can someone elaborate on this aspect some more perhaps?
the sound will be obvioulsy softer, because u are effectively killing all the sound and air that is moved from the back of the speaker, but you are also killing all the distortion and unwanted resonances that come with it. The spider and cone would also meet with less resistance when trying to move.
I dont need things to be very loud, so should i give this a shot? i can imagine that it might be dangerous for the driver if done without caution, can someone elaborate on this aspect some more perhaps?
Shpoop said:
All in all, that's a somewhat interesting idea. Of course, you would have to build drivers from scratch. If you ever do that, I'd love to hear how it goes!
The main problem to overcome is the force of air. Say you've got an 8 inch driver- that's 14 pounds per square inch on 50 square inches... 700 pounds!! You thought the sag from a vertically placed subwoofer was bad? 🙄
A complete vacuum??? 
I think peole often forget how strong atmospheric pressure really is............................................. how robust do you think this driver's surround material would have to be (just one thing out of twelve that comes to mind)
I think peole often forget how strong atmospheric pressure really is............................................. how robust do you think this driver's surround material would have to be (just one thing out of twelve that comes to mind)
well i was thinking of something like a jx53... a small 5 cm diameter, and its made out of aluminum
and i dont think it would be that hazardous to the driver...i mean if you buy a belljar and experiment with vacuums, things can hold up for a while. Yes, if it was a complete vacuum, as soon as the driver tried to push out it would probably just implode, and if it was wired reverse polarity, it would probably just keep going in and implode...but im sure you can get it pretty vacuum-ized while still being pretty safe
but the thing is, would the added difficulty moving out due to pressure create a terrible loss of sound quality? or if it didnt, would it be because theres enough air in the back, so all benefits arent there anymore?
and also, you wouldnt have to build them from scratch...im sure theres a way
and i dont think it would be that hazardous to the driver...i mean if you buy a belljar and experiment with vacuums, things can hold up for a while. Yes, if it was a complete vacuum, as soon as the driver tried to push out it would probably just implode, and if it was wired reverse polarity, it would probably just keep going in and implode...but im sure you can get it pretty vacuum-ized while still being pretty safe
but the thing is, would the added difficulty moving out due to pressure create a terrible loss of sound quality? or if it didnt, would it be because theres enough air in the back, so all benefits arent there anymore?
and also, you wouldnt have to build them from scratch...im sure theres a way
Shpoop said:
Ok, so it's only got 40 pounds pressing on it
Well.... here's a quick experiment. Take one of these drivers, and stack some weights on the cone. I'd be willing to bet you a pair of NSBs that the it would bottom out before the jx53 had more than 20 pounds on it. 40 pounds, for sure.
I honestly think that it could be done, if it was taken into consideration from the start. But you asked- would there be any benefits? I think that if you had two of these drivers playing bass in a bipole configuration, they could provide some benefits to linearity. The reaction forces on the cabinet would be canceled out since it's a bipole, and the lack of air could have benefits for linearity...
But you're talking about a 2 inch driver? As far as I know, we don't have a problem capturing and killing the back wave of a high/mid driver. Transmission lines with stuffing seem to be good at this- and B&W uses a stuffed tapered tube for that purpose.
In conclusion, I wouldn't recommend trying to evacuate a speaker enclosure; not even a little bit. Do it enough to have a physical effect and you'll break your driver, do it enough to count as having done it without breaking the driver, and you'll have the driver pushed way out of its equilibrium position, killing the linearity in BL and introducing all sorts of distortion.
I hope I don't sound like I'm discouraging you from asking all these questions- you're obviously new, curious, and interested in innovation.
Now not to stump your idea or anything (crazy ideas are good.. everyone into diyaudio has them.. it's almost like a prerequisite) I've certainly had a few myself. But..
I think if you lowered the box pressure any significant amount (even enough to just pull it inwards 5mm) it would definetly affect sound quality. The reason this matters is because half of the signal will be compressed (no pun intended really). The outward motion of the driver that is.
You can try it but I think you'll find that it's a waste of time. Especially for such a small driver like the jx53 you do'nt need to get into manic ideas like lowering the air pressure. You should be able to completely rid of the back wave using conventional methods.
It's a nice idea. But in practicaly terms it probably won't do you much good. If you find otherwise.. you can come back and make fun of me.
I think if you lowered the box pressure any significant amount (even enough to just pull it inwards 5mm) it would definetly affect sound quality. The reason this matters is because half of the signal will be compressed (no pun intended really). The outward motion of the driver that is.
You can try it but I think you'll find that it's a waste of time. Especially for such a small driver like the jx53 you do'nt need to get into manic ideas like lowering the air pressure. You should be able to completely rid of the back wave using conventional methods.
It's a nice idea. But in practicaly terms it probably won't do you much good. If you find otherwise.. you can come back and make fun of me.
Very insightful Shpoop!
WARNING: SHAMELESS PLUG FOLLOWS…
Check out my pending patent here , then let’s chat some more. I’ll try to get some pictures of my prototypes up on the web soon…
NOTE: If the link doesnt work, you can search uspto.gov for patent application publication number 20040136560 (Condensed speaker system).
-Casey Walsh
WARNING: SHAMELESS PLUG FOLLOWS…
Check out my pending patent here , then let’s chat some more. I’ll try to get some pictures of my prototypes up on the web soon…
NOTE: If the link doesnt work, you can search uspto.gov for patent application publication number 20040136560 (Condensed speaker system).
-Casey Walsh
if by exact opposite, u mean increasing the pressure in the enclosure...then that was gonna be my next idea too...although i cant seem to find any benefits except more air (and i thought the benefits of a bigger enclosure was not more air, but rather more space for the wave to bounce around or what have you)
and yes, it seems like that was part of his patent too
and yes, it seems like that was part of his patent too
To view the images at USPTO.com you need a tiff viewer plug-in. I highly recommend the one from alternatiff.com.
-Casey Walsh
-Casey Walsh
The idea I had was increasing the pressure in front of the driver, improving the driver's coupling with the air. You would need an acoustically transmissive membrane to hold in the air- and there's no reason you couldn't have a chamber behind it with an equal pressure of air. It would be like putting the speaker inside of a balloon.
Is it crazy? Yes. Horns are probably a way better way to go- but someone has already produced a membrane coupled to a conventional driver. Take a look over at Decware-
http://www.decware.com/panels.htm
I figure that since physics dictates that a horn must be a certain size due to the properties of air, why not change the properties of air?
Is it crazy? Yes. Horns are probably a way better way to go- but someone has already produced a membrane coupled to a conventional driver. Take a look over at Decware-
http://www.decware.com/panels.htm
I figure that since physics dictates that a horn must be a certain size due to the properties of air, why not change the properties of air?
The only problem with changing the properties of air (pressure) is that you can't do it in the space that YOU exist in!
Is the air pressure exactly the opposite weight in the the two opposing chambers?
Is the air pressure exactly the opposite weight in the the two opposing chambers?
sardonx said:
Yeah, that's the idea. That way the driver doesn't see a pressure across it, just a greater resistance to motion. It's got to push harder to move in either direction. You would need some sort of a membrane to keep air pressure in front of the driver. The membrane would be like a huge speaker diaphragm, you know?
No idea! I haven't tried it yet!
Ok, seriously- the advantage is that the driver would have to move only a short distance to produce a change in pressure representative of a certain amout of acousitic energy, due to the high air pressure. The idea is that this would propagate to the stretching membrane, and that it would produce more sound than the movement of the driver would have in free air because of the greater surface area of the membrane. Very similar to the advantage of a horn, mostly because the driver would not have to move very far, merely push harder.
Granted, there are tons of problems with the idea- it's probably not very linear.. the membrane would likely color the sound... the enclosure might be quite large (but could be waterproof 😉
This idea probably belongs at the half-bakery more than here at DIYaudio, so I think I'll leave it at that.
Ok, seriously- the advantage is that the driver would have to move only a short distance to produce a change in pressure representative of a certain amout of acousitic energy, due to the high air pressure. The idea is that this would propagate to the stretching membrane, and that it would produce more sound than the movement of the driver would have in free air because of the greater surface area of the membrane. Very similar to the advantage of a horn, mostly because the driver would not have to move very far, merely push harder.
Granted, there are tons of problems with the idea- it's probably not very linear.. the membrane would likely color the sound... the enclosure might be quite large (but could be waterproof 😉
This idea probably belongs at the half-bakery more than here at DIYaudio, so I think I'll leave it at that.
Yes.. the inplementation would take a lot of work and money.. which would perhaps be better off spend on 4 massive carbon fiber diaphram drivers isobarically stuffed into a small coffin and equilized with a linkwitz circuit flat to 10 hz using a massive 2000 watt amp.
In stereo.
In stereo.
Yer kidding right?
You'll suck the cone into the vacume. Or.. how do you plan on coupling the driver to the airless environment behind it? You'd need an acoustically transparant but perfectly air tight seal, which I think is an oxymoron. Am I missing something?
The point of having air behind the speaker in a sealed sub is that the air is required to control the cone movement. The point of the box in a sealed sub is to kill the backwave, and contain air pressure.
You'll suck the cone into the vacume. Or.. how do you plan on coupling the driver to the airless environment behind it? You'd need an acoustically transparant but perfectly air tight seal, which I think is an oxymoron. Am I missing something?
The point of having air behind the speaker in a sealed sub is that the air is required to control the cone movement. The point of the box in a sealed sub is to kill the backwave, and contain air pressure.
. . . . there you have it folks, the blind leading the blind through a discussion of one of the dumbest ideas I've heard in quite a while.
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